Apparatus for taking gas samples in shaft furnaces

ABSTRACT

Apparatus for taking gas samples in shaft furnaces, particularly blast furnaces, which is normally located outside the furnace and which is introduced into the furnace for sampling purposes. The apparatus comprises a probe equipped with a vibrator to facilitate its movement into the furnace charge.

United States Patent Kiintziger et al.

APPARATUS FOR TAKING GAS SAMPLES IN SHAFT FURNACES Inventors: Ernest P.Kiintziger; Nicolas Lemmens, both of Assenede,

Belgium Assignee: S.A. des Anciens Etablissements Paul Wurth, LuxembourgLuxembourg Filed: Aug. 24. 1973 Appl, No.: 391,361

Foreign Application Priority Data 1 June 10, 1975 Primary ExaminerS.Clement Swisher 57 1 ABSTRACT Apparatus for taking gas samples in shaftfurnaces, particularly blast furnaces, which is normally located p 1973Luxcmhflufg 65993 outside the furnace and which is introduced into thefurnace for sampling purposes. The apparatus com- C 73/4215 133/1 l3prises a probe equipped with a vibrator to facilitate its Int. Cl. v i ii i t i i i i i i i i i movgmenl into [he furnace cha gg Field Of Search73/4215 R, 42l .5 A, 425,

73/4352; 138/11 1, 113; 175/19 9 Clams 4 Drawmg F'gures f i 6 5 56 f2 24s Q a L.

PATENTEDJUH 10 1915 SHEET L T-ECLlZIB PATENTEDJUH 10 I975 APPARATUS FORTAKING GAS SAMPLES IN SHAFT FURNACES BACKGROUND OF THE INVENTION 1.Field of the Invention The invention relates to an apparatus for takinggas samples in shaft furnaces, particularly blast furnaces, which in theinoperative position is located outside the blast furnace and which isintroduced into the blast fur nacc charge for taking gas samples(operating position).

Taking reduction gas samples from the blast furnace and the knowledge oftheir chemical composition will in the future become of increasinglydecisive importance for controlling the blast furnace process relativeto optimum furnace working. To obtain informative reproducible measuredvalues it is usual to take the gas samples in the blast furnace charge.

2. Description of the Prior Art It is known to take the indicated gassamples from the blast furnace by means of probes. For this purposeeither probes which are arranged fixedly in the blast furnace or movableprobes introduced radially into the blast furnace are used. Furthermore.a probe installation is known which comprises a cross-beam passing fromwall to wall at right angles through the blast furnace charge and whichserves as a support for a displaceable probe head for taking gassamples.

However. the known probe installations have general and specificdisadvantages which will be briefly explained hereinafter.

Gas probes arranged rigidly in the blast furnace, due to theircumbersome construction resulting from the harshness of the operatingenvironment have a detrimental influence on the blast furnace materialflow at the point of gas sampling. Frequently below the gas probe aspace containing no material is formed which disturbs the reduction gasflow as a result of the artificially created space free of material andfalsifies the measured values.

The prior art movable tubular probes comprise a probe support which isarranged with the end thereof projecting into the blast furnace. Inoperation, the reduction gas is sucked into the probe duct and is passedeg to a collecting tank arranged outside the blast fur nace forsubsequent chemical analysis. A drivearranged outside the blast furnacemoves the probe horizontally into or out of the blast furnace. Fortaking gas samples at different furnace radii the probe is movedstepwise to the different points. However, as a result it is impossibleto avoid a spacing in time of the individual gas sampling operations. Asa result of the time lapse between the individual sampling operations noinformative reproducible gas picture in the blast furnace can beobtained because a change in the gas resulting from the process canfalsify the measured values during sampling. Moreover. as a result ofthe long dwell time of the probe in the blast furnace the possiblity ofdamage through overheating of the probe and slipping of the charge isincreased. In some cases the probe is actually destroyed and/or lost.For these reasons the known introductible probes generally haverelatively large diameters in order to increase their resistance to hightemperature and buckling stresses. As a result the same disadvantagesoccur at least during the measurements as with fixed probes the furnacecharge is disturbed and an inaccurate sampling of the reduction gasesresults.

As regards the probe displaceably arranged on a cross beam located inthe furnace, quite apart from the extremely cumbersome constructions inthe furnace which take up the space required for other importantoperating devices such a probe has the disadvantages of the two types ofprobe construction mentioned hereinbeforc.

The apparently most appropriate known construction comprises a probe fortaking gas samples which may be moved into and out of the charge of ashaft furnace, particularly a blast furnace. in the radial directionwhich is provided with a plurality of removal apertures along itslongitudinal axis in each case connected with a pipe which permits theremoval of gas samples at sew eral points over the furnace diameter.Such probes are for example described in U.S. Pat. No. 3,240,069 andGerman DAS 1,533,829. They permit the simultaneous removal of gassamples at several points of the furnace cross-section whichconsiderably reduces the dwell time of the probe in the furnace formeasurement purposes. The present invention relates to this type ofprobe.

It has now been found that although the time necessary for themeasurement is greatly reduced prior art multi'apertured movable probesstill require a relatively long time to be moved into and out of thefurnace charge so that the overall dwell time of the probe in thefurnace is still too long.

It is an object of the invention to bring about the rapid introductionand withdrawal of a gas sampling probe relative to the furnace charge.whereby the gas sampling probe is introduced into and removed from thefurnace radially and namely in such a way that the gas removing deviceintroduced into the furnace charge permits the obtaining of aninformative overall picture of the reduction gas in the furnace withoutdisturbing furnace working without any major influence on thedistribution of the furnace charge.

A further object of the present invention is to avoid the disadvantagesof the existing installations to the greatest possible extentparticularly relative to considerably reducing the total dwell time ofthe probe in the furnace by combining an effective cooling with a highrigidity of the probe.

These objects are generally considered to be of the greatest importanceand several proposals have already been made for the solution thereof.Thus according to previously mentioned German DAS 1,533,829 the probe isgiven a rotary movement on introduction or the outer end of the probe ismounted on guide rollers and its displacement takes place by means of ahydraulic cylinder piston drive.

SUMMARY OF THE INVENTION The present invention relates to a gas removaldevice or probe including a vibrator which acts upon the same during thedisplacement movement of the probe. The resultant vibration during linermotion considerably facilitates the introduction and removal of theprobe relative to the furnace charge and considerably reduces the dwelltime of the probe in the furnace for the purpose of taking gas samples.

A preferred embodiment of the invention further involves a specialconstruction which has an effective cooling and, despite the limitedsize, a high rigidity. The reduction in size without sacrificingrigidity or cooling capacity is achieved by arranging a plurality offurnace gas sampling pipes within an outer cylindrical protective tubearound a central pipe, whereby these sampling pipe lines are connectedwith the apertures formed in the casing of the outer protective tube inorder to permit the simultaneous sampling of gas at several points alongthe probe. Water circulation for cooling the probe is maintained in thecentral pipe and in the free space between the central pipe and theouter protective tube not occupied by the pipe lines.

The construction according to the invention, which comprises twoconcentrically arranged pipes whose interspace is substantially filledby a plurality of pipe lines which supply the gas samples to ananalyser. ensures the rigidity of the probe with smallest possibledimensions. The movement of the probe into the furnace charge is thusfurther considerably facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS:

The present invention may be better understood and its numerous objectsand advantages will become apparent to those skilled in the art byreference to the accompanying drawings relative to a preferredembodiment. wherein:

FIG. 1 is a schematic side elevation view of a portion of a shaftfurnace including a sampling probe installation in accordance with thepresent invention;

FIG. 2 is a cross sectional view showing a complete array of gas entryports in a probe in accordance with a first embodiment of the invention,FIG. 2 being taken at an angle along the entire length of the probe andthe gas entry ports actually being longitudinally spaced along theprobe;

FIG. 3 is a cross sectional side elevation view ofa single gas supplypipe of the probe of FIG. 2: and

FIG. 4 is a cross sectional view of the free end of a second embodimentof a probe in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

According to FIG. I, which represents a longitudinal section through theprobe installation, a probe 2 is mounted so as to be horizontallyintroduced into and withdrawn from the blast furnace 4. In theinoperative position (withdrawn position) the probe 2 is arranged on asliding or guide block 6 on a working platform. On the end of guideblock 6 remote from blast furnace 4 is attached a servo motor 8 which isconnected with probe 2 via, for example. an endless chain (not shown inFIG. I). Motor 8, via the chain or other transmission means, deliverslongitudinal force to move probe 2 in the horizontal direction.

Furthermore the probe is provided with a pneumatic or hydraulicallyoperated vibrator 10. The vibrations produced are superimposed on thetension or pressure exerted by servo-motor 8 on probe 2 andsubstantially aid the movement of probe 2 into the blast furnace charge.

A cut off valve 12 on the blast furnace wall 14 is opened to introducethe probe 2 and is closed with the probe 2 in the inoperative position.In order to seal the inside of the blast furnace relative to the outeratmosphere with the probe 2 introduced, the valve 12 is provided with alabyrinth seal device.

As according to the invention with the aid of probe 2 simultaneouslyseveral gas samples are taken at different furnace radii in the chargein order not to provide a falsified gas diagram probe 2, as shown inFIG. 2 probe 2 is provided with a certain number of apertures or gasentry ports 18, 20, 22, 24, 26, 28, 30, 32 and 34 on its cylindricalouter casing 16. The number of apertures I8 to 34 corresponds to thedesired number of gas samples to be taken at the various blast furnaceradii. To each aperture 18, 20, 22, 24, 26, 28, 30, 32 and 34 isconnected a gas distribution pipe 36, 38, 40, 42, 44. 46, 48, 50, 52.These gas distribution pipes 36 to 52 are distributed over the inside ofthe outer casing I6 and are held in their particular position by meansof a supporting tube 54 located centrally and concentrically to outercasing 16. As all the gas distri' bution tubes 36 to 52 of theembodiment of FIG. 2 run parallel to the outer casing 16 or supportingtube 54, apertures 18 to 32 are longitudinally and angularly dis placedover outer casing 16 and are perpendicular to the appropriate gasdistribution pipes 36 to 52.

All the gas supply pipes 36 to 52 are connected to a distributor system56 located outside blast furnace 4 (FIG. I). from which distributorsystem 56 the different gas samples are simultaneously supplied viaseparate pipe lines to collecting tanks.

To prevent damage through heating of the probe 2 in the blast furnace 4probe 2 is water cooled. The cooling water flow up to the tip of theprobe may take place through hollow chamber 58 (FIGS. 2 3 and 4) whichis bounded by gas distribution pipes 36 to 52, outer casing 16 andsupporting tube 54. The cooling water return flow takes place throughthe inside 60 of support ing tube 54.

In a further development the cooling water supply takes place throughthe inside of supporting tube 54 and the return flow via hollow chamber58. This results in a particularly favourable cooling of the tip of theprobe.

Whereas in the above described embodiment of FIG. 2 the gas entryapertures of gas distribution pipes 36 to 52 are angularly distributedover the complete periphcry of the protective casing 16. In accordancewith a further embodiment, as depicted in FIG. 4, the gas inletapertures are only longitudinally displaced and not an gularlydisplaced. To this end the gas distribution pipes 36 to 52 are twistedaround the supporting tube 54. The gas distribution pipes of the FIG. 4embodiment will, of course, be parallel at any given point along thelength of the probe and the maximum twist about the support tube 54imparted to any distribution pipe will be less than 360.

The FIG. 2 embodiment which comprises the straight gas distributionpipes has the advantage that it can be produced in a very simple manner.In the FIG. 4 embodiment, however, all the gas inlet apertures are inthe same plane.

FIG. 3 represents a longitudinal section through one of the gasdistributing pipes and through the appropriate inlet aperture 18. InFIG. 3 a gas distribution pipe 36 terminates at a point adjacent to theoutwardly disposed edge of inlet aperture 18. Furthermore a thermocouple62 around which the gas flows is provided in gas distribution pipe 36. Asignal commensurate with temperature as provided by the thermocouple ispassed on to an indicator. Due to the relatively short dwell time ofprobe 2 in blast furnace 4 the thermocouple 62 must have a rapidresponse time thermocouples or other temperature sensors have beenomitted from FIGS. 2

and 4 in the interest of facilitating understanding of the invention.

To complete the gas diagram in the blast furnace out side the blastfurnace a gas pressure indicator or recording device can be connected toeach individual gas distribution pipe. Thus. on the various furnaceradii the chemical composition. temperature and pressure of thereduction gas may be measured. These measured values can be used forcontrolling the complete blast furnace process.

Regarding the operation of the probe according to the invention it ispointed out that prior to the introduction of probe 2 into blast furnace4 valve 12 is. for ex ample. hydraulically opened. During theintroduction of probe 2 with the aid of servo-motor 8 and vibrator lcompressed air is introduced through distributor valve 56 into gasdistribution pipes 36 to 52 for keeping free the apertures during theintroduction process of the probe. The introduction of the probe 2 intoits operating position takes a maximum of l seconds. The compressed airsupply to the gas distribution pipes is now disconnected and reductiongas now flows through the gas distribution pipes to distributor valve56. As residual quantities of compressed air are still present in thegas distribution pipes this reduction gas compressed air mixture isfirst blown out into the atmosphere before the reduction gas is passedinto the avail able collecting tanks or analyzers. Approximately 30seconds are necessary for carrying out this complete operation. Thesubsequent removal of the probe from the blast furnace takes a further15 seconds so that the total sampling time up to removal of the probeamounts to one minute. Under normal circumstances this time is notexceeded. Besides the technical and time advantages it is also stressedthat the simple construction of the probe allows for very smalldimensions. Thus the external diameter of the outer casing 16 can belimited in one embodiment to 60.3 mm. The limited probe diameter doesnot disturb the reduction gas picture and does not falsify the measuredvalues.

To facilitate the movement of the probe into the furnace charge it isadvantageous to use a vibrator similar to those used in percussiondrills or mechanical picks.

While a preferred embodiment has been shown and described. variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly. it is to beunderstood that the present invention has been described by way ofillustration and not limitation.

What is claimed is:

1. Apparatus for taking gas samples from a plurality of locations withinthe charge burden on the hearth of a shaft furnace comprising:

moveable probe means. said probe means including an elongated probeadapted to be introduced into and withdrawn from the furnace charge viaa port in the furnace wall. said elongated probe including a centralsupporting tube and a plurality of rigid gas sampling pipessymmetrically arranged around said supporting tube. said gas samplingpipes each being provided with a gas entry aperture. said gas entryapertures being individually displaced along the longitudinal axis ofthe probe. said probe further comprising a tubular outer sheathsurrounding said gas sampling pipes. said sheath being concentric withsaid central supporting tube and being provided with a plurality of gasentry ports individually displaced along the longitudinal axis of theprobe.

said gas entry ports being individually coupled to respective of saidgas entry apertures in said gas sampling pipes, said sheath and centralsupporting 5 tube defining an annular housing for said gas samplingpipes and a path for coolant flow in the free interspace between saidsampling pipes;

drive means for applying longitudinal force to said probe means to urgesaid probe means into and to withdraw said probe means from the furnacecharge; and

vibrator means coupled to said probe means for superimposing vibratorymovement on to the longitu dinal force during introduction of the probeinto the furnace charge.

2. The apparatus of claim 1 wherein said movable probe means centralsupporting tube is provided with an opening adjacent the free end ofsaid probe means whereby a coolant may be delivered to the interspacebetween said sheath and supporting tube adjacent the free end of saidprobe means. said coolant flowing along said probe in said freeinterspace.

3. The apparatus of claim 1 further comprising:

temperature sensing means disposed in at least some of said gas samplingpipes for indicating the temperature of the gas entering said probemeans through the gas entry port coupled to the gas entry aperture inthe sampling pipe in which the temper ature sensing means is installed.

4. The apparatus of claim 1 wherein all of said sampling pipes areoriented parallely to one another 5. The apparatus of claim 1 wherein anaxial twist relative to said supporting tube is imparted to said probemeans gas sampling pipes to thereby place all of said gas entryapertures in a single plane which passes through the axis of said probemeans.

6. The apparatus of claim 2 further comprising: temperature sensingmeans disposed in at least some of said gas sampling pipes forindicating the temperature of the gas entering said probe means throughthe gas entry port coupled to the gas entry aperture in the samplingpipe in which the temperature sensing means is installed. 7. Theapparatus of claim 6 wherein all of said sampling pipes are orientedparallely to one another.

8. The apparatus of claim 7 wherein an axial twist about said supportingtube is imparted to said parallel gas sampling pipes to thereby placeall of said gas entry apertures in a common plane through the axis ofsaid probe means.

9. A method for taking gas samples in a shaft furnace which comprisesthe steps of:

imparting longitudinal force to an elongated sampling probe to causesaid probe to extend inwardly through the wall of a furnace into thecharge burden on the furnace hearth. said probe being characterized by aplurality of spacially longitudinally displaced gas entry ports. each ofsaid ports being coupled to a separate gas sampling pipe;

superimposing vibratory motion onto said longitudinal force to minimizedisruptions of the furnace charge burden during probe insertion into theburden;

delivering gas at a pressure in excess of the internal furnace pressureto the gas entry pipes in the probe during introduction of the probeinto the furnace;

7 8 circulating a coolant through the probe during the ameter thefurnace gases entering the probe time the probe is introduced into thefurnace; through the entry ports and being delivered via thediscontinuing the supply of pressurized gas when the sampling pipes tothe exterior of the furnace; and probe is inserted into the furnace tothe desired powithdrawing the probe after the gas samples have sition tothereby permit the simultaneous taking of been taken.

gas samples at several points over the furnace di-

1. Apparatus for taking gas samples from a plurality of locations withinthe charge burden on the hearth of a shaft furnace comprising: moveableprobe means, said probe means including an elongated probe adapted to beintroduced into and withdrawn from the furnace charge via a port in thefurnace wall, said elongated probe including a central supporting tubeand a plurality of rigid gas sampling pipes symmetrically arrangedaround said supporting tube, said gas sampling pipes each being providedwith a gas entry aperture, said gas entry apertures being individuallydisplaced along the longitudinal axis of the probe, said probe furthercomprising a tubular outer sheath surrounding said gas sampling pipes,said sheath being concentric with said central supporting tube and beingprovided with a plurality of gas entry ports individually displacedalong the longitudinal axis of the probe, said gas entry ports beingindividually coupled to respective of said gas entry apertures in saidgas sampling pipes, said sheath and central supporting tube defining anannular housing for said gas sampling pipes and a path for coolant flowin the free interspace between said sampling pipes; drive means forapplying longitudinal force to said probe means to urge said probe meansinto and to withdraw said probe means from the furnace charge; andvibrator means coupled to said probe means for superimposing vibratorymovement on to the longitudinal force during introduction of the probeinto the furnace charge.
 2. The apparatus of claim 1 wherein saidmovable probe means central supporting tube is provided with an openingadjacent the free end of said probe means whereby a coolant may bedelivered to the interspace between said sheath and supporting tubeadjacent the free end of said probe means, said coolant flowing alongsaid probe in said free interspace.
 3. The apparatus of claim 1 furthercomprising: temperature sensing means disposed in at least some of saidgas sampling pipes for indicating the temperature of the gas enteringsaid probe means through the gas entry port coupled to the gas entryaperture in the sampling pipe in which the temperature sensing means isinstalled.
 4. The apparatus of claim 1 wherein all of said samplingpipes are oriented parallely to one another.
 5. The apparatus of claim 1wherein an axial twist relative to said supporting tube is imparted tosaid probe means gas sampling pipes to thereby place all of said gasentry apertures in a single plane which passes through the axis of saidprobe means.
 6. The apparatus of claim 2 further comprising: temperaturesensing means disposed in at least some of said gas sampling pipes forindicating the temperature of the gas entering said probe means throughthe gas entry port coupled to the gas entry aperture in the samplingpipe in which the temperature sensing means is installed.
 7. Theapparatus of claim 6 wherein all of said sampling pipes are orientedparallely to one another.
 8. The apparatus of claim 7 wherein an axialtwist about said supporting tube is imparted to said parallel gassampling pipes to thereby place all of said Gas entry apertures in acommon plane through the axis of said probe means.
 9. A method fortaking gas samples in a shaft furnace which comprises the steps of:imparting longitudinal force to an elongated sampling probe to causesaid probe to extend inwardly through the wall of a furnace into thecharge burden on the furnace hearth, said probe being characterized by aplurality of spacially longitudinally displaced gas entry ports, each ofsaid ports being coupled to a separate gas sampling pipe; superimposingvibratory motion onto said longitudinal force to minimize disruptions ofthe furnace charge burden during probe insertion into the burden;delivering gas at a pressure in excess of the internal furnace pressureto the gas entry pipes in the probe during introduction of the probeinto the furnace; circulating a coolant through the probe during thetime the probe is introduced into the furnace; discontinuing the supplyof pressurized gas when the probe is inserted into the furnace to thedesired position to thereby permit the simultaneous taking of gassamples at several points over the furnace diameter, the furnace gasesentering the probe through the entry ports and being delivered via thesampling pipes to the exterior of the furnace; and withdrawing the probeafter the gas samples have been taken.